1. Field of the Invention
This invention relates to hinges for casement windows.
2. Prior Art
When designing hinges for windows pivotable about a horizontal axis, located about centrally in the window opening, two main points must be considered. On the first hand the hinge shall permit a simple mounting and dismounting, respectively, of the frame with respect to the casement, while maintaining a safe retention of the frame therein, also when the frame has been swung about 180.degree. for cleaning its outer pane, and on the other hand the hinge must contain frictional elements ensuring a smooth and well balanced turning movement.
There are a number of hinges available on the market having one frictional component between its attachment to the casement and to the frame, respectively, but with those hinges the frictional component will follow the frame during the initial 90.degree. of the opening movement. During this initial turning movement a lower frictional center of the component is active. During the further 90.degree. of a full turning movement an upper frictional center at the component is active. When the frame is being returned the initial 90.degree. of the turning movement will occur about the upper center of the frictional component. Thereafter the frictional movement will accompany the frame so the remainder of the turning movement will occur about the lower frictional center of the frictional component.
Each frictional center in those hinges must have a frictional force sufficient to carry the full weight of the window, as each center will alone have to take care of the braking effect during part of the movement.
In order to provide the desirable possibility to mount the frame in the casement the hinge often includes a link, so the frame, after a 180.degree. rotation, will be brought at least partly outside the sealing shoulder in the casement.